Common flaws in the analysis of river sediments polluted by risk elements and how to avoid them: case study in the Ploučnice River system,Czech Republic

Journal of Soils and Sediments - River channel sediments have been widely used to trace current and historical pollution in fluvial systems, although they are not the only media employed for that...     

Changes in Mercury Deposition in a Mining and Smelting Region as Recorded in Tree Rings

The adsorption of lead onto date palm fibers (palm fibers) and leaf base of palm (petiole) has been examined in aqueous solution by considering the influence of various parameters such as contact time, solution pH, adsorbent dosage, particle sizes, ionic strength, and temperature. The adsorption of Pb(II) increased with an increase of contact time. The optimal range of pH for Pb(II) adsorption is 3.0?C4.5. The linear Langmuir and Freundlich models were applied to describe the equilibrium isotherms, and both models fitted well. The monolayer adsorption capacity of Pb(II) on palm fibers and petiole was found as 18.622 and 20.040 mg/g, respectively, at pH 4.5 and 25°C. Dubinin-Radushkevich (D-R) isotherm model was also applied to equilibrium data. The mean free energy of adsorption (2.397 and 4.082 kJ/mol) onto palm fibers and petiole, respectively, may be carried out via physisorption mechanism. Pseudo-first-order rate equation and pseudo-second-order rate equation were applied to study the adsorption kinetics. In comparison to first-order kinetic model, pseudo-second-order model described well the adsorption kinetics of Pb(II) onto palm fibers and petiole from aqueous solution. From the results of the thermodynamic analysis, Gibbs free energy ??G, enthalpy change ??H, and entropy ??S were determined. The positive value of ??H suggests that interaction of Pb(II) adsorbed by palm fibers is endothermic. In contrast, the negative value of ??H indicates that interaction of Pb(II) ions by petiole is exothermic. The negative value of ??G indicates that the adsorption of Pb(II) ions on both palm fibers and petiole is a spontaneous process.     

Sensitivity of root pruned ‘Conference’ pear to water deficit in a temperate climate

The present study examines the need for irrigation in pear trees (Pyrus Communis, cv. ‘Conference’) under low evaporative demand conditions, like in Belgium, in order to maintain a consistent fruit yield and high fruit size. To determine the sensitivity of the pear yield under low evaporative demand conditions three different orchards were monitored. The study shows that a Ψ_soil of −60 kPa during shoot growth has no effect on fruit yield but lower Ψ_soil values induced a decline in both fruit size and total yield. Just as for arid environments a Ψ_stem of −1.5 MPa is related to negative yield responses. In dry conditions lower Ψ_soil and Ψ_stem values were observed in root pruned trees compared to not root pruned trees in the same irrigation treatment, however without yield decline. In one orchard a biannual bearing tendency was observed after root pruning. Furthermore intensive Ψ_soil measurements show a high variation in Ψ_soil between orchards, and within an orchard. This underlines the need for irrigation management on a parcel level and the need for new irrigation scheduling techniques which take the spatial variation in the orchard into account.     

Influence of soil temperature and moisture on micronutrient supply,plant uptake,and biomass yield of wheat,pea, and canola

Abstract

Crop yield response to micronutrient fertilization is difficult to predict, particularly under unfavorable environmental conditions as these may alter both crop nutrient demand and the soil micronutrient supply to plant roots. The research objective was to evaluate the effect of various soil temperature and moisture conditions on crop growth response to added micronutrient copper (Cu), zinc (Zn), and boron (B) along with soil micronutrient supply and distribution among fractions. Brown and Dark Brown farm soils collected from southern Saskatchewan were used to grown wheat, pea and canola within controlled environment chambers. The biomass yields of all crops decreased under cold soil temperature and moisture stress (drought and saturated) conditions. Greater plant uptake of Cu, Zn, and B was associated with optimum (i.e., field capacity) soil moisture and warm temperature (23°C) growing conditions, compared to drought (i.e., 50% field capacity), saturated, and cold (5°C) temperature conditions. Environmental stress had the greatest impact on pea growth, reducing crop yield and micronutrient utilization efficiency more than 95%. Soil supplies of Cu and Zn were most negatively impacted by drought stress due to reduced mobility of these diffusion limited nutrients. The extractable micronutrients levels and chemical speciation fractions of Cu, Zn, and B indicating that bioavailability and micronutrient transformation were not affected during our short-term (i.e., six-weeks) study. However, it is suggested that assessments of micronutrient forms also be conducted on soil samples under actual moisture and temperature conditions as they exist in the experiment, as well as on dried, processed samples.     

Is the long-term application of sewage sludge turning soil into a sink for organic pollutants?: evidence from field studies in the Czech Republic

Purpose

Long-term microscale field experiments established at four sites in the Czech Republic (since 1996) were used for an assessment of the severity of the wide-scale contamination of treated soils by persistent organic pollutants (POPs) and pharmaceuticals and personal care products (PPCPs) as a result of the long-term regular pollutant load via sewage sludge and farmyard manure applications and for an estimation of the potential environmental risk caused by long-term pollutant inputs to agricultural soils.

Material and methods

The experimental plots were treated as follows: (i) NPK mineral fertilization (NPK); (ii) sewage sludge (SS1); (iii) sewage sludge applied at three times the rate compared to SS1 (SS2); (iv) farmyard manure (FYM); and (v) untreated control. Except for antibiotics, which showed results for all analyses below the detection limit, all groups of the analyzed compounds showed measurable contents in the treated soils.

Results and discussion

Among the POPs, the levels of organochlorine pesticides (OCPs) were detected at two locations at levels exceeding the Czech preventive values for their contents in agricultural soils (7.5 μg/kg for dichlorodiphenyl trichloroethane family, 20 μg/kg for hexachlorbenzene, and 10 μg/kg for α-hexachlorocyclohexane), regardless of the treatment. Similarly, elevated contents of polycyclic aromatic hydrocarbons (PAHs) were occasionally observed without any substantial relationship to the fertilizer application scenario. Thus, these contaminants are connected with atmospheric deposition in the given areas (PAHs) and their long-term stability (OCPs) even several decades after their ban; the role of the fertilizer composition was negligible.

Conclusions

The levels of per- and polyfluoroalkylated substances, brominated flame retardants, and synthetic musk compounds tended to increase in the sewage sludge–treated plots, indicating that sewage sludge can contribute to the abundance of these compounds in soil, although the contaminant levels determined do not represent a direct environmental risk. The levels of these contaminants in sewage sludge and sludge-treated soils should be regularly monitored in further research.

     

Red clover Trifolium pratense L. phytoestrogens: UV-B radiation increases isoflavone yield, and postharvest drying methods change the glucoside conjugate profiles

Isoflavone extracts of red clover Trifolium pratense L. (cv. Pawera) with dissimilar glucoside conjugate profiles were obtained by employing different postharvest drying methods. The most prominent isoflavones found were formononetin and biochanin A and their corresponding glucosides and malonyl glucoside esters. Postharvest freeze drying inhibited the conversion of the glycosides to the aglycones, while vacuum drying allowed for maximum conversion of the glycosides to their corresponding aglycones. Air drying produced a low level of the aglycones formononetin and biochanin A, and oven drying promoted decarboxylation of the malonyl glucosides to the acetyl glucosides. Exposure to enhanced UV-B radiation resulted in an increase in total formononetin and biochanin A isoflavone levels, indicating that harvest during a period of high ambient UV-B radiation may be appropriate for maximum yield. The levels of caffeic acid and flavonols also increased by about 40 and 250%, respectively, on exposure to enhanced UV-B radiation.     

Collecting plant genetic resources in Cuba. Report on the fourth mission,March 1989

Summary Report is given about the fourth joint mission INIFAT-ZIGuK to the provinces of Guantánamo and Santiago de Cuba in March 1989, within the agreement between the Academy of Sciences of Cuba and the Academy of Sciences of the German Democratic Republic. The area explored was rich in plant genetic resources. Agriculture is often still practiced in a traditional way, and it was possible to show the influence of different ethnic groups. A total of 238 accessions of vegetables, pulses and other species was collected. A great variation was found inPhaseolus lunatus L. andVigna species. Old cultivars of maize and pumpkins were collected. Valuable information about the use of different plants in folk medicine could be gathered.

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Sammlung pflanzlicher genetischer Ressourcen in Kuba. Bericht über die vierte Sammelreise, März 1989

Zusammenfassung Es wird über die vierte gemeinsame Sammelreise INIFAT-ZIGuK in den Provinzen Guantánamo und Santiago de Cuba, die im März 1989 im Rahmen des Abkommens zwischen der Akademie der Wissenschaften Kubas und der Akademie der Wissenschaften der DDR stattfand, berichtet. Das Sammelgebiet zeichnete sich durch seinen Reichtum an pflanzlichen genetischen Ressourcen aus. Die Landwirtschaft wird oft noch in der traditionellen Weise praktiziert, und es war möglich, den Einfluß unterschiedlicher Bevölkerungsgruppen nachzuweisen. Insgesamt wurden 238 Muster von Gemüsen, Hülsenfrüchten und anderen Arten gesammelt. Eine große Variabilität wurde beiPhaseolus lunatus L. und beiVigna-Arten gefunden. Wertvolle Informationen zur Nutzung der verschiedenen Pflanzen in der Volksmedizin konnten gesammelt werden.

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. , 1989

- - , 1989 . . , . 238 , . Phaseolus lunatus L. Vigna. .

     

Dormancy breaking in Fagus sylvatica seeds is linked to formation of abscisic acid-glucosyl ester

New Forests - Seed dormancy is an adaptive mechanism that allows seed germination under suitable environmental conditions. Germination of stored dormant seeds proceeds after dormancy breaking...     

Field maple and hornbeam populations along a 4-m elevation gradient in an alluvial forest

Tree species composition of Central European alluvial hardwood forests has changed with the arrival of flood-intolerant and mesic species. Within this group of tree species, a dominant role is played by field maple (Acer campestre) and European hornbeam (Carpinus betulus). This study was performed in the Lanzhot natural forests at the confluence of the Morava and the Dyje Rivers, which are considered to be one of the most natural alluvial hardwood forests in Central Europe and where the absence of the direct influence by humans for 75 years has allowed spontaneous development. Our basic research questions were as follows: (1) does the mutual proportion and structure of field maple and hornbeam populations change along an elevation gradient of 4 m in an alluvial forest and (2) does the tree spatial pattern of field maple and hornbeam change along this gradient? The study found significant differences in the development of hornbeam and field maple populations with increasing elevation in an alluvial hardwood forest. While the strength of the hornbeam population clearly increases with increasing elevation, the field maple population does not. Compared to hornbeam, field maple is closer to the r-strategy side of the K-r continuum on alluvial sites. Our study reveals that field maple and hornbeam are mainly distributed in clusters on alluvial sites. Both species are concentrated at places with lower flooding intensity, i.e. to higher elevation sites. The study shows that tree spatial patterns could change dynamically along a short elevation gradient in alluvial hardwood forest.